borg/docs/quickstart.rst

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.. include:: global.rst.inc
.. _quickstart:
Quick Start
===========
This chapter will get you started with |project_name|. The first section
presents a simple step by step example that uses |project_name| to backup data.
The next section continues by showing how backups can be automated.
A step by step example
----------------------
1. Before a backup can be made a repository has to be initialized::
$ borg init /mnt/backup
2. Backup the ``~/src`` and ``~/Documents`` directories into an archive called
*Monday*::
$ borg create /mnt/backup::Monday ~/src ~/Documents
3. The next day create a new archive called *Tuesday*::
$ borg create --stats /mnt/backup::Tuesday ~/src ~/Documents
This backup will be a lot quicker and a lot smaller since only new never
before seen data is stored. The ``--stats`` option causes |project_name| to
output statistics about the newly created archive such as the amount of unique
data (not shared with other archives)::
Archive name: Tuesday
Archive fingerprint: 387a5e3f9b0e792e91ce87134b0f4bfe17677d9248cb5337f3fbf3a8e157942a
Start time: Tue Mar 25 12:00:10 2014
End time: Tue Mar 25 12:00:10 2014
Duration: 0.08 seconds
Number of files: 358
Original size Compressed size Deduplicated size
This archive: 57.16 MB 46.78 MB 151.67 kB
All archives: 114.02 MB 93.46 MB 44.81 MB
4. List all archives in the repository::
$ borg list /mnt/backup
Monday Mon Mar 24 11:59:35 2014
Tuesday Tue Mar 25 12:00:10 2014
5. List the contents of the *Monday* archive::
$ borg list /mnt/backup::Monday
drwxr-xr-x user group 0 Jan 06 15:22 home/user/Documents
-rw-r--r-- user group 7961 Nov 17 2012 home/user/Documents/Important.doc
...
6. Restore the *Monday* archive::
$ borg extract /mnt/backup::Monday
7. Recover disk space by manually deleting the *Monday* archive::
$ borg delete /mnt/backup::Monday
.. Note::
Borg is quiet by default. Add the ``-v`` or ``--verbose`` option to
get progress reporting during command execution.
Automating backups
------------------
The following example script backs up ``/home`` and ``/var/www`` to a remote
server. The script also uses the :ref:`borg_prune` subcommand to maintain a
certain number of old archives::
#!/bin/sh
REPOSITORY=username@remoteserver.com:backup
# Backup all of /home and /var/www except a few
# excluded directories
borg create --stats \
$REPOSITORY::`hostname`-`date +%Y-%m-%d` \
/home \
/var/www \
--exclude /home/*/.cache \
--exclude /home/Ben/Music/Justin\ Bieber \
--exclude '*.pyc'
# Use the `prune` subcommand to maintain 7 daily, 4 weekly
# and 6 monthly archives.
borg prune -v $REPOSITORY --keep-daily=7 --keep-weekly=4 --keep-monthly=6
.. backup_compression:
Backup compression
------------------
Default is no compression, but we support different methods with high speed
or high compression:
If you have a quick repo storage and you want a little compression:
$ borg create --compression lz4 /mnt/backup::repo ~
If you have a medium fast repo storage and you want a bit more compression (N=0..9,
0 means no compression, 9 means high compression):
$ borg create --compression zlib,N /mnt/backup::repo ~
If you have a very slow repo storage and you want high compression (N=0..9, 0 means
low compression, 9 means high compression):
$ borg create --compression lzma,N /mnt/backup::repo ~
You'll need to experiment a bit to find the best compression for your use case.
Keep an eye on CPU load and throughput.
.. _encrypted_repos:
Repository encryption
---------------------
Repository encryption is enabled at repository creation time::
$ borg init --encryption=passphrase|keyfile PATH
When repository encryption is enabled all data is encrypted using 256-bit AES_
encryption and the integrity and authenticity is verified using `HMAC-SHA256`_.
All data is encrypted before being written to the repository. This means that
an attacker who manages to compromise the host containing an encrypted
archive will not be able to access any of the data.
|project_name| supports two different methods to derive the AES and HMAC keys.
Passphrase based encryption
This method uses a user supplied passphrase to derive the keys using the
PBKDF2_ key derivation function. This method is convenient to use since
there is no key file to keep track of and secure as long as a *strong*
passphrase is used.
.. Note::
For automated backups the passphrase can be specified using the
`BORG_PASSPHRASE` environment variable.
Key file based encryption
This method generates random keys at repository initialization time that
are stored in a password protected file in the ``~/.borg/keys/`` directory.
The key file is a printable text file. This method is secure and suitable
for automated backups.
.. Note::
The repository data is totally inaccessible without the key file
so it must be kept **safe**.
.. _remote_repos:
Remote repositories
-------------------
|project_name| can initialize and access repositories on remote hosts if the
host is accessible using SSH. This is fastest and easiest when |project_name|
is installed on the remote host, in which case the following syntax is used::
$ borg init user@hostname:/mnt/backup
or::
$ borg init ssh://user@hostname:port//mnt/backup
Remote operations over SSH can be automated with SSH keys. You can restrict the
use of the SSH keypair by prepending a forced command to the SSH public key in
the remote server's authorized_keys file. Only the forced command will be run
when the key authenticates a connection. This example will start |project_name| in server
mode, and limit the |project_name| server to a specific filesystem path::
command="borg serve --restrict-to-path /mnt/backup" ssh-rsa AAAAB3[...]
If it is not possible to install |project_name| on the remote host,
it is still possible to use the remote host to store a repository by
mounting the remote filesystem, for example, using sshfs::
$ sshfs user@hostname:/mnt /mnt
$ borg init /mnt/backup
$ fusermount -u /mnt